Various fasteners have been used on inexpensive or disposable garments such as diapers, including lengths of pressure-sensitive adhesive coated tape, snaps, and hook and loop type fasteners.
When lengths of pressure-sensitive adhesive coated tape are used, typically first end portions of the tape are adhered to the disposable garments when they are manufactured, and second end portions of the tape are adhered to the garments by the users to hold the garments in place. Typically such lengths of pressure-sensitive adhesive coated tape are cut from long yardage rolls of tape during manufacture of the disposable garments, and to facilitate unwinding of the rolls either a release coating is provided on the side of the tape opposite the pressure-sensitive adhesive or the adhesive is covered by a release liner which must be removed prior to attachment of the tape to the garments. Such lengths of pressure-sensitive adhesive coated tape have been widely used as the fasteners for disposable diapers, however the presence of relatively small amounts of contaminants such as talcum powder or baby oil either on the pressure-sensitive adhesive or on the portion of the garment to which the pressure-sensitive adhesive is to be adhered by the user greatly reduces the reliability of the fastener.
The use of hook and loop fasteners on inexpensive or disposable garments such as diapers substantially overcomes this problem of reduced fastener reliability due to contaminants such as talcum powder or baby oil, but the mating portions of such fasteners are difficult to attach with pressure-sensitive adhesive in the conventional manner by cutting and applying pressure-sensitive adhesive coated fastener portions from long yardage rolls of supply material. The pressure-sensitive adhesive will adhere to the surface of the fastener material against which it is wound on the roll unless a release coating is provided on the fastener material, which is difficult and impractical, or unless the adhesive is covered by a release liner which must be removed prior to attachment of the fasteners to a garment.
U.S. Pat. Nos. 3,694,867; 3,773,580 and 3,849,840 have described the use of a hot melt or thermoplastic adhesive for applying hook and loop type fasteners to garments, however neither describes a suitable system by which such portions of fasteners could be properly applied to many inexpensive garments such as disposable diapers which include an easily heat and pressure distorted thin polyolefin film or nonwoven layer to which the fastener must be adhered.
U.S. Pat. No. 3,694,867 to Stumpf describes mechanically releasably engageable fastener portions having backing layers of adhesive for which examples of thermoplastic resins are given, however the adhesives described are not suitable for adhesion to easily heat and pressure distorted thin polyolefin film or nonwoven layer of the type used on disposable diapers.
U.S. Pat. No. 3,773,580 to Provost describes a method for attaching a fastener to a substrate by coating the substrate with a first adhesive, heat activating a second adhesive on the fastener, and then pressing the two adhesives together to affix the fastener to the substrate. This method is not suitable for high speed production of inexpensive garments, however, because among other things, the difficulty associated with applying adhesive on the thin heat-sensitive film or nonwoven layer or substrate, and because of the cost of using two adhesive layers.
U.S. Pat. No. 3,849,840 to Yamada et al. describes using pressure-sensitive adhesive to attach "velvet type" fasteners, after indicating that applying fasteners with thermoplastic adhesive often results in damage to the fasteners "from both or either the pressure and/or the heat applied", which problem is particularly acute if the fastener is partially or totally made of heat sensitive materials such as polyolefinic materials. Additionally, damage from such heat and pressure can occur to substrates to which the fasteners are adhered, such as the easily distorted thin polyolefin film or nonwoven layers of disposable diapers to which fasteners are attached.